The present invention generally relates to plastic containers for beverages, particularly carbonated soft drink products and the like. More specifically, this invention relates to a blow molded plastic container, and to a method of forming that container, having at least one outward bulge immediately adjacent the body portion. This outward bulge portion has the practical effect of lending improved grip and manual handling characteristics to the container.
The use of plastic containers to package beverages, especially carbonated soft drink products, has been remarkably successful since such containers were first introduced in the 1970s. The widespread application of these containers primarily stems from the fact that the plastic material from which they are made can be biaxially oriented. These plastic materials, it may be noted, are invariably thermoplastics, most especially polyesters such as polyethylene terephthalate (PET).
Biaxial orientation involves aligning the polymer chains in two directions, and the consequence of this orientation is a closer, more orderly packing of material. The practical benefits of this phenomenon are two fold: first, containers thus oriented can be produced with thin walls, often as a direct result of the orienting process itself; and second, the mechanical strength and gas barrier properties of these thin wall containers increases dramatically upon biaxial orientation. The overall result is a container that is light weight, yet extremely robust.
A number of ways are known to fabricate these biaxially oriented containers. The most commercially important of these fabrication procedures, however, are those that employ stretch blow molding techniques. These techniques generally utilize a preform or parison, typically produced by way of injection molding, that is heated, or cooled, as the case may be, to at or near the glass transition temperature of the material. When at this temperature, the preform is placed into a blow mold in which the preform is longitudinally stretched by a stretch rod and horizontally expanded by air or other operating gas pressure. The resulting product is a container whose body and shoulder portions have relatively thin walls and are biaxially oriented.
Although the thin wall construction of biaxially-oriented containers is advantageous overall, there are, nevertheless, some drawbacks to this construction. For example, because of its thin nature, the container wall has little tolerance for a topical configuration that is other than smooth, uniform and continuous. Thus, even though it may be desirable to provide alterations or embellishments to the wall, it has been difficult to do so without adversely affecting the mechanical integrity of the wall.
Of the efforts made in this regard are those directed to providing the container walls with designs or features, such as ridges or ribs in the shoulder portions of such containers, in order to improve the consumer""s ability to hold and handle the container. While important improvements have been made in this regard, the art still recognizes a continuing need to develop a container design or feature that will improve the consumer""s ability to grip and handle the container and that will not detract from the mechanical integrity of the container.
An object of this invention is to improve plastic, blow molded beverage containers.
Another object of the present invention is to provide a plastic, blow molded beverage container with improved handling characteristics.
A further object of this invention is to bulge outwardly one or both of the shoulder and base portions of a plastic, blow molded beverage container to make it easier to grip and to handle the container.
Another object of the present invention is to employ a greater than ambient pressure, present when a plastic, blow molded beverage container is filled with a beverage, to form two spaced apart bulges in the container that facilitate gripping and handling the container.
These and other objective are attained with a blow molded plastic beverage container, comprising a neck portion adapted to receive a closure, a body portion, a shoulder portion integrally connected to and extending between the neck portion and the body portion, and a base portion integrally connected to and extending from the base portion and closing a bottom end of the container. A bulge is formed in one, or both, of the shoulder and base portions bulging to facilitate gripping and handling the container. Preferably, a respective bulge is formed in each of the shoulder and base portions, forming a pair of bulges that bracket the container body. Also, preferably, grooves are formed in the shoulder and base portions of the container to facilitate formation of the bulges.
The container is formed in a multi-step process from a preform that may have a conventional design. In this process, the preform is expanded into an initial container shape having a neck portion, a shoulder portion, a body portion, and a base portion. That container is filled with a beverage, and a bulge is formed in one, or both, of the shoulder and base portions of the container. Preferably, the bulge or bulges are formed while the container is being filled with the beverage. For example, the container may be filled with a beverage at greater than ambient pressure, and this greater than ambient pressure may be used to bulge the shoulder and base portions outwardly of the container body.
Further benefits and advantage of the invention will become apparent from a consideration of the following detailed description, given with reference to the accompanying drawings, which specify and show preferred embodiments of the invention.